pandas DataFrame groupby()

import pandas as pd
df=pd.DataFrame([['a',2,5],
                 
                 ['b',3,6],
                 ['c',5,8],
                 ['a',7,3],
                 ['c',6,9]],columns=['A','B','C'])

df.groupby(['A'])['B'].max() 
A
a    7
b    3
c    6
Name: B, dtype: int64

df.groupby(['A'])['B'].sum()
A
a     9
b     3
c    11
Name: B, dtype: int64

df.groupby(['A'])['B'].mean()A
a    4.5
b    3.0
c    5.5
Name: B, dtype: float64